Silicon photonics is often considered one of the most popular and successful technology platforms based on planar photonics circuits for cost effective optoelectronics integration. Optical waveguide-based photonics devices such as lasers, modulators, and detectors are typically fabricated on silicon-on-insulator (SOI) wafers. In SOI photonic systems, light is typically confined in a wafer (or chip) plane. Silicon waveguides are typically designed with submicron cross-sections, allowing dense integration of active and passive devices to achieve higher speed and lower driving power. Due to the high refractive index contrast between silicon and other media (e.g., air or glass), the numerical aperture (NA) of light exiting the silicon chip may be larger than the typical NA of optic fibers. Optical mode converters (OMCs) are typically used to improve optical coupling between optical waveguides and optic fibers. However, existing OMCs may not always provide desired efficiency and/or bandwidth and may cause polarization dependency above a desired level.